Abstract: Electrochemical devices with metal casings have been considered incompatible with nuclear magnetic resonance (NMR) spectroscopy because the oscillating magnetic fields (“rf fields”) responsible for excitation and detection of NMR active nuclei do not penetrate metals. According to the present invention, rf fields can still efficiently penetrate into nonmetallic layers of electrochemical cells (such as a coin cell battery configuration) provided the magnetic field is oriented tangentially to the electrochemical cell electrodes in a “skimming” orientation. As an example, noninvasive high field in situ 7Li and 19F NMR of an unmodified commercial off-the-shelf rechargeable coin cell was demonstrated using a traditional external NMR coil setup. The in operando NMR measurements revealed that irreversible physical changes accumulate at the anode during electrochemical cycling.

Abstract: Electrochemical devices with metal casings have been considered incompatible with nuclear magnetic resonance (NMR) spectroscopy because the oscillating magnetic fields (“rf fields”) responsible for excitation and detection of NMR active nuclei do not penetrate metals. According to the present invention, rf fields can still efficiently penetrate into nonmetallic layers of electrochemical cells (such as a coin cell battery configuration) provided the magnetic field is oriented tangentially to the electrochemical cell electrodes in a “skimming” orientation. As an example, noninvasive high field in situ 7Li and 19F NMR of an unmodified commercial off-the-shelf rechargeable coin cell was demonstrated using a traditional external NMR coil setup. The in operando NMR measurements revealed that irreversible physical changes accumulate at the anode during electrochemical cycling.

Abstract: Provided are systems, methods, and apparatus for using nuclear magnetic resonance (NMR) to detect a first material in the presence of a second material within a region of the Earth and within a static magnetic field (such as Earth's magnetic field). These inventions are uniquely suited to detect NMR signals from materials remotely located from a measurement device (e.g., below ice with the device above the ice). They are further useful in detecting first material having relatively short spin-lattice (T1) relaxation time in the presence of second material having longer T1 relaxation time (and therefore slower response to applied magnetic fields). Two pre-polarization currents are used to create pre-polarization magnetic fields stronger than the static magnetic field, each applied over a period of time between the first material's T1 relaxation time and the second material's T1 relaxation time, enabling different ways to null the NMR signal from the second material.

Abstract: An MR method and system of determining elements of the apparent diffusion coefficient tensor in a material with plurality of anisotropic structural units that can be too small to be resolved by direct imaging. MR data is acquired with MR system including pulse sequences, the sequences including imaging or spectroscopy pulse sequences with a series of embedded diffusion-sensitizing gradient waveforms with different gradient strength applied to the material. A nonlinear function of a b-value corresponding to the pulse sequence is defined and the acquired MR data is processed according to defined nonlinear function. Images/maps of the components of the tensor of apparent diffusion coefficients, corresponding to anisotropic structural units, based on the processed MR data, are created. A method of evaluating of the geometrical parameters of lung airways is also described.

Abstract: An MR method and system of determining elements of the apparent diffusion coefficient tensor in a material with plurality of anisotropic structural units that can be too small to be resolved by direct imaging. MR data is acquired with MR system including pulse sequences, the sequences including imaging or spectroscopy pulse sequences with a series of embedded diffusion-sensitizing gradient waveforms with different gradient strength applied to the material. A nonlinear function of a b-value corresponding to the pulse sequence is defined and the acquired MR data is processed according to defined nonlinear function. Images/maps of the components of the tensor of apparent diffusion coefficients, corresponding to anisotropic structural units, based on the processed MR data, are created. A method of evaluating of the geometrical parameters of lung airways is also described.

Abstract: A method using nuclear magnetic resonance techniques to detect corrosion within metallic structures such as aluminum under non-ferromagnetic coatings without first having to remove the coatings. The metallic structure is placed within an external static magnetic field. A series of radio frequency preparation and inspection pulses is applied to the metallic with the preparation pulses, and for generating a series of nuclear magnetic resonance response signals with the inspection pulses. The response signals are detected and the amplitudes of the response signals are compared with the spin--spin relaxation time of corrosion for detecting the presence of corrosion in the structure.

Abstract: Thermal damage in resin-matrix composite materials is detected using a low field NMR nondestructive testing technique. The technique involves subjecting the resin-matrix composite material to an NMR measurement of the spin-lattice relaxation (T.sub.1) at a low magnetic field strength and/or the spin-lattice relaxation of local field order (T.sub.1D) at any field strength. Thermal damage is evident as an increase in T.sub.1 and T.sub.1D.

Abstract: Methods and apparatus for monitoring and controlling cure cycles of composite structures utilize specialized NMR sensor (14) embedded into critical regions in the interior of composite structures (18) to provide in-situ cure state information. Signals developed by the NMR sensors (14) during the curing cycle are processed by an NMR spectrometer (30) to determine selected NMR parameters including T.sub.1, T.sub.2, T.sub.1D, and T.sub.2 * of the materials in the vicinity of the sensor, from which the rigidity of the materials are deduced. Experimental data show clear trends in values of particular NMR parameters taken as time series during cure cycles. Cure cycle control is accomplished using output data from an enhanced NMR spectrometer (30*) to drive temperature and pressure controllers (38, 42) of a curing oven (20*) for real time process control.

Abstract: Apparatus for sensing particles in a fluid medium comprising an ultrasonic resonant cavity for containing a fluid medium. A first transducer on one side of the cavity continuously propagates thereacross ultrasonic compressional waves whose phase and amplitude are perturbed by the presence of particles in the fluid medium. A second transducer positioned on the opposite side of the cavity from the first transducer substantially parallel to and in registry therewith receives the ultrasonic waves and converts them to rf electric waves of the same frequency, the rf electric waves having their phases and amplitudes modulated in response to any perturbations in the ultrasonic waves. The rf waves are amplified and fedback to the first transducer thereby to establish an oscillatory circuit.